Figure 8.

Dependence of four first-order diffractions on incident angle and polarization. Four first-order diffractions (0,1), (0,−1), (1,0), and (−1,0)
with TM and TE incident light on incident angle. (a) and (b) show the FODE at
λ0
with incident light in the Γ−X
direction with different θ, while (c) and (d) show it with different ϕ
at θ=
60°.